Railway signaling.



H. A. WALLACE.

RAILWAY SIGNAUNG.

APPLlCATIoN man JUNE m, 1914.

Et: N

WITNESSES FICE@ HERBERT A. WALLACE, OF NEW YORK, N. ASSIGNOR TO THE UNION SWITCH 81;

SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYL- VANIA.

RAILWAY sIGNALINe.

Specification of Letters Patent.

Patented June 26, 19017.

Original application filed November 8, 1913, Serial No. 799,911. Divided and this application led .Tune 18,

1914. Serial No. 845,765.

To all whom t may concern: j

Be it known that I, HERBERT A. WALLACE, a citizen oi the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Railway Signaling, of which the following is a specification.

My invention relates to railway signaling systems in which the signals are controlled by track circuits. More particularly my Ainvention relates to signaling for governing traflic in both directions over a stretch of single track.

The present application is a division of my pending application, Serial'No. 79 9,911, iile'd November 8, 1913, for railway signaling systems, which latter is a continuation of my application tiled May 28, 1909, Serial No. 498,883.

I will describe one form of signaling system embodying my invention, and will then.

point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view illustrating a stretch of railway track over which cars or trains travel in both directions and having applied thereto a signaling system embodying my invention.

Referring to thedrawing, A designates a stretch of railway track over which traiiic moves in both directions. As here shown, I provide a track section C-C, which is electrically isolated from the rest of the track by insulated rail joints a. The track section C-C is provided with a track circuit comprising the rails of the section, two relays R and R, connected with the rails adjacent the ends of the section respectively, and a source of alternating signaling current connected with the rails adjacent the middle of the section. As here shown the source of signaling current is a transformer T, whose secondary is connected with the rails of the section, and whose primary is connected with mains f, f to which alternating signaling current is supplied from a source F. The track relays R and R are preferably of a type which will respond to the alternating signaling current but not to direct current, and in the drawing this is indicated in the conventional manner by diagonal lines in the relays.

With an arrangement of track circuit such as I have just described, that is, with the source of signaling` current connected at about the middle of the track circuit and a relay at each end thereof, I have observed in practice that as a car or train enters one end of the track circuit it will open the track relay adjacent that end only and that the track relay at the other end of the track circuit is opened only when the car or train has reached a point at a distance from the point of connection of the signaling current with the track rails, depending upon the length o1' track circuit. Jalso, after the car or train has passed about the same distance beyond this point of connection, the relay first opened again closes, the relay at the exit end remaining open,` however, until after the car or train leaves the track circuit. In this invention I have taken advantage of the foregoing facts by arranging railway signals to be controlled by relays as hereinatter explained.

S designates a signal governing tratlic in the direction of arrow 49, which signal is located adjacent the point at which the relay R is opened by a. car or train moving in the direction of arrow 49, and which signal is controlled by relay R. The circuit for signal S is from one side of battery I3 through contact 1 of relay R', wire 2, mechanism of signal S, wire 3, common return wire 0 to battery P. Another signal, S', governing trathc in the direction of arrow 50, is located adjacent the point at which relay R is opened by a car or train moving in such direction, and is controlled by relay R. The circuit for signal S is from one side of battery P through contact of relay R, wire 4, mechanism of signal S, wire 5, common return wire O to battery I).

rI`he operation of the system is as follows: As a train ory car moving in the direction of arrow 49 enters section C--C, relay R will be de'energized, thereby causing signal S to indicate danger or stop. Signal S will remain in the danger position until after the car or train passes it, as relay Rwill not pick up until the car or train. haspassed beyond that point. As the train passes signal S, this signal will change to danger indication, since when the train passes this point relay R will be denergized, thereby opening the circuit for signal S at Contact l,

of relay R. Signal S will not change to the clear position until relay R closes, that is, until the train has passed out of the track section C-C- The operation of the apparatus during the passage of a car. or train in the direction of arrow will be similar to that just explained. The point at which a car or train moving through the track section C-C will cause the track relay at the exit end of the section to open is some-- what variable due to conditions of the trackway as to moisture, etc. The average location of this point is indicated on the drawing by the line designated-point at which relay R (R) opens. In order to prevent a signal from changing to danger before it is reached by an approaching train, the signal should bc located at least as 'far in the rear of the point of connection of the transformer with the track as the extreme position in the rear of that point at which a car or train will under any circumstances cause the relay at the exit end of the section to open. In accordance with the usual practice, the signal is preferably located even a short distance in the rear of this extreme position, so that the signal does not change to danger until after it has been passed by the front end of a car or train. This loca-- tion of the signals is indicated on the drawing. My invention provides a preliminary section eXtending from each signal S and S' to the adjacent end of the section C-C, and hence it is impossible to bring two cars or trains together in the space between the signals. A system of this type is particularly adapted for the protection of a single track through tunnels over bridges, etc. By means of my present invention, I employ one'track vcircuit to perform functions for which three-track circuits have heretofore been required.

Although I have not herein shown or described any means for supplying motive power to the cars or trains traveling along f the railway, it is understood that signaling systems embodying my invention, are equally well adapted for use on railways using any form of motive power, such for example as steam, electricity, or compressed air. Nor do lI wish to limit myself to alternating signaling current in the track circuits, for the reason that direct signaling current may be used instead, the arrangement of track relays, source of signaling current, and sig- Y nals remaining the same.

Although I have herein shown and described only one form of signaling system embodying my invention, it is understood that various changes and modications may be made therein within the scope of the Copies of this patent may be obtained for trolled by the relay at the other end, said signal being located adjacent the point at which apcar or train passing through the section from the first-mentionedend opens the relay at the last-mentionedY end, and a' second signal located between'the source of current and the last-mentioned end and controlled by the relay at the rst-mentioned end, saidsecond signal being located 'adjacent the point at which a car or train passing through the section toward the iirstf" mentioned end opens the rst-mentioned relay.` f

2. In combination, a section of railway* track over which traic moves in both directions, a source of signaling current connected with the track rails adjacent the middle of the section, two track relays one connected with the track rails adjacent each end of the section, and two' signals located on opposite sides respectively'of the point of connection of the source with the track rails and each controlled by the track relay on the other side of said point, each-signal being locatedy adjacent the point at which the relay which controls it is opened by a car or train passing through the section toward the relay.

3. In combination, a section of railway track over which traffic moves in both directions, a source of alternating signaling cur- Y rent connected with the track rails adjacent the middle of the section, two track relays one adjacent each end of the section, and

-two signals located on opposite sides respectively of the point of connection of the source with the track rails and each controlled by the track relay on the other side of said point, each signal being located adjacent the point at which Athe relay whichb controls it is opened by a -car orV train passing through the section toward the relay.

In testimony whereof I affix my in presence of two witnesses;

HERBERT A. wLLAcE.

Witnesses :V

M. L. Kamm, G. A. GAUGHAN.

ve cents each, by addressing the Goinmissioner'of Patents,

Washington, D. G.

signature 

